Core and method of making conduits



lay 26, 1925.

T. E. MURRAY CORE AND METHOD OF MAKING CONDUITS Filed April 20, 1923 DNN /f/J @V ,QN um mm w yvm.

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Conduits are frequently made in locations where it is inconvenient to provide suiicient clearance to remove extremely long cores and such cores are often of such great length that their weight and rictional drag on the side of the conduit makes removal very difficult and in many cases practically impossible.

As illustrated in Fig. 3 the conduits terminate at the wall 28 of a man-hole or vault 30 formed in a pavement or t-unnel. The usual dimensions of such vaults or manholes will not permit the removal of integral cores of great length. lThe sectional core herein disclosed is made up oi a number of short lengths which are proportioned to be readily withdrawn by a workman in a man hole or vault of limited dimensions. The arrangement of pulling straps 22 and shouldered rings 24 is such that the sections can be successively removed one at a time. 1

In removing the cores the operator lirst inserts a tool 32 in the end of' the iii'st section 16 so that the prongs 34 spring into engagement with the shouldered ring 2O oi the end section. IIe then pulls thev tool outward, for example as shown in Fig. 3, until the first section 16 is entirely withdrawn from the conduit. This action will bring the ends 24 of the pulling straps 22 of the First pulled section into engagement with the shouldered ring 2O of the next` section 14. Further pulling on the section 16 will then cause the section 14 to be withdrawn from the face 2S of the conduit wall whereupon the pulling straps 22 o1 the iirst removed section can be collapsed and disconnected `trom the section 14 and said section canbe pulled out in asimilar manner. As this section is withdrawn the hooked ends 24 of its pulling straps will engage the shouldered ring 2O of the section 12 and this section will likewise be pulled out.`

This manner of removingthe sections in successive stages divides the work or pulling load sufficiently to enable the workman to withdraw the sections without undue exertion or strain. In pulling the strap ci one section into position to engage the shouldered ring20 of the second section, a blow can be exerted which tends to start the uncoupling movement ol one section to the other. Such a blow is more effective than a direct pull and affords an effective means 'For starting the separating movement.

The separate sections can be o1` different diameters if desiredso as to permit of easy removal. Then they are of different diameters the section most remote from the pulling end is of the smallest diameter and the succeeding sections are of gradually increasing diameters toward the pullingeiid. As thus arranged it is apparent that as the succeeding sections are pulled fromf the ing molded conduit they pass through gradually increasing diameters. ation of diameter spaces of The varibetween the separate sections may be very slight and is preferably just suflicient to permit sections to move freely through the conduit.

As shown in Fig. 4, where comparatively short conduits are to be formed, I may join the adjacent sections of the core by means of a bayonet joint, the drawing showing a sleeve 84 secured to one of the sections 36, telescopically engaging an 38, having a lug secured thereto which is adapted to engage the bayonet slot 42.

Though I have described with great pai'- ticularity certain embodiments of the invention shown, and steps inkcarrying out my improved inethod,`it is not to be construed that I am limited thereto, as changes may be made by those skilled in the art without departing from the invention as deined in the appended claims.

IWhat I claim is: j

1. A core for molding conduits of great length comprising a series of non-collapsible sections arranged to be successively removed one at a time from one end of the conduit.

2. A core for molding conduits of great length comprising a series of rigid non-collapsible sections and means for withdrawing certain sections separately without moving other sections. i

3. A core of the class described comprisa plurality of rigid tubular sections detachably connected to one another and arranged so that certain sections can be successively withdrawn without moving other sections.

4. A core comprising a plurality of noncollapsible tubular sections and connecting means whereby one section can be first pulled longitudinally without moving its adjacent section and later pulled simultaneously with said adjacent section.

5.y A core of the class described comprising a plurality of rigid metallic tubes having an outer sheath and means for successively withdrawing said tubes from the sheath.

6. A core comprising a plurality of single piece tubular sections and connecting means between said sections whereby one can be first pulled longitudinally away -from the other and later pull the other with it so as to permit the dismantling of a comparatively loiig core in a short space.

7. A core comprising a plurality of tubular sections each having a sleeve adapted to -telescopically engage an adjacent section,

and each having a resilient pulling strap and a projection, the latter parts being arranged so that the sections can be successively separated and disconnected from one another.v

8. A core of the class described comprisadjacent section l ing a series of tubes arranged end to end, the projection of each having a fixed projection near one end the different secti and a forwardly extending pulling member and uncoupled by secured at the opposite end. member.

9. A core of the class described compris- In ing a series of tubes arranged end to end, signed my nam each having a fixed projection at one end and a resilient member adapted to engage THOMAS E, MURRAY.

an adjacent tube, whereby s can be readily coupled l0 flexing said resilient whereof, I have hereunto 

